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ICD-10-CM 2027

ICD-10 code for IBS (irritable bowel syndrome)

K58.9

Irritable bowel syndrome, unspecified

✓ Billable / specific

Confirmed by the official ICD-10-CM index entry “irritable, irritability › bowel (syndrome)”. Page updated September 29, 2026.

About coding IBS

The ICD-10-CM code for IBS (irritable bowel syndrome) is K58.9 (Irritable bowel syndrome, unspecified). The official index lists 4 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on K58.9.

Within K58, choose K58.9 (unspecified) only when documentation doesn't support a more specific option: with diarrhea (K58.0), with constipation (K58.1), mixed irritable bowel syndrome (K58.2) and other irritable bowel syndrome (K58.8).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 391 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders with MCC, relative weight 1.2392) and DRG 392 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders without MCC, relative weight 0.7645), in MDC 06 (Diseases and Disorders of the Digestive System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

Related IBS codes

  • K58.0 Irritable bowel syndrome with diarrhea
  • K58.1 Irritable bowel syndrome with constipation
  • K58.2 Mixed irritable bowel syndrome
  • K58.8 Other irritable bowel syndrome

Common questions about IBS ICD-10 codes

What is the ICD-10 code for IBS?

K58.9 — Irritable bowel syndrome, unspecified. More specific codes apply when the documentation supports them: K58.0, K58.1, K58.2, K58.8.

What is the ICD-10 code for irritable bowel syndrome with diarrhea?

K58.0 — Irritable bowel syndrome with diarrhea.

What is the ICD-10 code for irritable bowel syndrome with constipation?

K58.1 — Irritable bowel syndrome with constipation.

What is the ICD-10 code for mixed irritable bowel syndrome?

K58.2 — Mixed irritable bowel syndrome.

What is the ICD-10 code for other irritable bowel syndrome?

K58.8 — Other irritable bowel syndrome.

Is K58.9 billable?

Yes. K58.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can K58.9 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict K58.9 as a principal diagnosis.

Is K58.9 a CC or MCC?

No. K58.9 is neither a CC nor an MCC under MS-DRG v44.0.